Communication between fire fighters wearing a self-contained breathing apparatus, such as a safety face mask, for example, is extremely difficult under the best conditions and almost impossible in most fire situations. Fire fighters must yell through their masks or use elaborate hand signals, or in some cases, may even remove their mask, just to be able to talk to each other.
Since fire fighting often requires split-second decision making, often with serious consequences at stake, there is a need for rapid and coherent communication to avoid exposing fire fighters and the public to undue risk.
Existing mechanisms typically employ a microphone which is “push-to-talk” activated and coupled via an interface box and corded link to a speaker placed in proximity to a wearer's ear, thereby providing a walkie-talkie type arrangement. A wearer of the self-contained breathing apparatus must push a button to talk into the microphone, which requires that the wearer can only have one hand free while talking into the apparatus. Moreover, a voice signal picked up by the microphone is usually amplified to be presented to a speaker of another user, which often picks up interference in the form of ambient noise encountered in most fire situations. This interference can cause false triggering of voice detection circuitry. In addition, the geometry of the cavity inside the self-contained breathing apparatus enhances low frequencies, making analog voice signals virtually unintelligible. The cord connecting the microphone and speaker to the interface box can often frustrate a user as it can become entangled in other fire fighting equipment or the user's clothes, or it may loosen and become detached, preventing communication between fire fighters. In short the cord can be a safety hazard. In addition, the absence of communication with a fire fighter may indicate that the fire fighter is in a dangerous situation and that the other members of the crew should locate and help the person in need, possibly in a smoke-filled room with zero visibility.
A known fire fighter's communications apparatus, system and method is disclosed in patent application WO 03/103773 A1. A method of facilitating communications for a wearer of a mask, such as a fire fighter's breathing apparatus, involves receiving a removable transmitter apparatus in a receptacle in the mask, to permit the transmitter apparatus to receive acoustic utterances made by the wearer of the mask and to transmit electromagnetic radiation representing the utterances for reception by a receiver. The receiver, which is positioned at the waist of the fire fighter, receives the electromagnetic radiation and broadcasts an audible reproduction of the acoustic utterances. The receiver may be supported by a wearer of the mask so that listeners in the vicinity of the wearer can hear the utterances. A plurality of wearers of masks may each have the apparatus described above to create a mobile public address system in which the utterances of a plurality of wearers may be broadcast from each wearer to other people in the vicinity of the wearers.
However the known system, apparatus and the method have problems in particularly for group communication and/or data transport. Also, there's no automated voice communication i.e. user must perform some level of manual activation to open the channel and sometimes that is not possible when the alarm is on. However the major problem is that the wireless, i.e. radio, communications between the breathing apparatus (i.e. fire fighter's mask) and the worn receiver of the breathing apparatus is only one-way communications. This emerges major difficulties in group and data communications for modern safety and emergency equipments.
Another known protective mask communication device and system is known from a patent publication U.S. Pat. No. 6,121,881. The systems allow wearers of protective masks working in a hazardous area to readily communicate both with each other and with personnel and automated systems outside of the area. Preferred systems provide Bluetooth communications between mask wearers. Furthermore the mask has a higher power transceiver communicating to and from a remote transceiver located further than the other masks. The higher power communications is used to identify the mask and is actuated by an actuator in the mask.
However the Bluetooth transmission between the safety masks is too weak and has too small coverage in order to allow fire fighters to work effectively. Typical coverage range of Bluetooth is so small that the fire fighters may easily drift away from the coverage range of the mask communication system, thereby losing contact with the group. This is a clear safety hazard. However major problem is the actual group creation. In particularly problem arise when establishing or changing the group composition or use conditions. For example the group composition may be needed to change or amend, even on the fly, group members (remove or add fire fighters), rename the group, use different frequencies, channels or transmission power, use different network parameters, etc. This is particularly relevant for real-time safety hazard situations such as during the fire accident.